400 INTRODUCTION TO CYTOLOGY 



factors of the system, i.e., the extent to which the latter factors can be 

 made to assume or to share in the differential function. 



In many plants and animals the genie sexual differences have been 

 correlated with visible and constant differences in the chromosomes. 

 This serves to emphasize the necessity of considering cytological and 

 genetical data in any attempt to understand sex and its control. 



